1. Field of the Invention
The present invention relates to an image reading device and is suitable for a digital copying machine, an image scanner, and the like.
2. Description of the Related Art
Illuminating units included in known image reading devices employ light-emitting diodes (hereinafter abbreviated to LEDs) that are highly durable and highly efficient in light utilization. An image reading device disclosed by Japanese Patent Laid-Open No. 2012-160940 employs an illuminating unit including LED light sources that are provided at two respective long-side ends of a light-guiding member (the type of such an illuminating unit is hereinafter referred to as two-end source type), whereby the illuminance is increased and the nonuniformity in illuminance is reduced.
The illuminating unit of the two-end source type disclosed by Japanese Patent Laid-Open No. 2012-160940, however, needs to include spaces for providing the light sources at the two respective ends of the light-guiding member. Therefore, the size of such an image reading device tends to be large.